Iceland has closed its main international airport after a volcanic eruption sent a plume of ash, smoke and steam 12 miles into the air.

The airport and air traffic control operator Isavia said no flights were taking off or landing at Keflavik airport.

A spokeswoman said the ash plume from the Grimsvotn volcano was covering Iceland, but "the good news is that it is not heading to Europe". She said it was blowing north-west toward Greenland instead.

She said officials were investigating whether Iceland's other airports could take Keflavik-bound flights.

Transatlantic flights were being diverted away from Iceland, and there was no sign yet that the eruption would cause the widespread travel disruption triggered last year by ash from the Eyjafjallajokull volcano.

Grimsvotn, which lies under the uninhabited Vatnajokull glacier, began erupting on Saturday, for the first time since 2004.

Pall Einarsson, a geophysicist at the University of Iceland, said last year's eruption was a rare event and Grimsvotn was likely to have much less of an effect on international air traffic.

"The ash in Eyjafjallajokull was persistent or unremitting and fine-grained," Einarsson said. "The ash in Grimsvotn is more coarse and not as likely to cause danger as it falls to the ground faster and doesn't stay as long in the air as in the Eyjafjallajokull eruption."

Iceland is one of the world's most volcanically active countries and eruptions are frequent. Grimsvotn volcano also erupted in 1998, 1996 and 1993. The eruptions have lasted between a day and several weeks.